The overall objectives of this project are to investigate the vaccine potential of the PI attachment protein of Mycoplasma pneumoniae and the F fusion protein of respiratory syncytical virus (RSV) and to develop oral recombinant adenovirus vaccines by the use of recombinant DNA technology. The PI protein mediates the attachment of M. pneumoniae to respiratory epithelium whereas the F protein plays an important role in the replication of RSV in the lung. Evidence suggests that the PI protein of M. pneumoniae and the F fusion protein of RSV are both major immunogens. An adenovirus vector was chosen because experience in the military has shown that protection from adenovirus infection in the respiratory tract can be effectively and safely achieved with orally administered live vaccines. In this present research we propose 1) to construct an epitope map for the identification of epitopes relevant to the protective immunity, 2) to construct recombinant adenovirus containing the PI coding sequence for optimal antigen expression, 3) to synthesize a full length cDNA for the F protein from the Long strain of subgroup A RSV, 4) to construct an epitope map of the RSV F protein, 5) to construct recombinant adenoviruses containing coding sequences of the RSV F protein, 6) to investigate whether pulmonary cytotoxic T lymphocytes can be induced in experimental animals with the recombinant adenoviruses-RSV hybrid vaccine candidate, 7) to assess the expression and immunogenicity of PI and F protein produced by the recombinant adenoviruses in a small animal model, and 9) to examine the safety of these recombinant vaccines in a small animal model. These specific aims interface biological immunological and molecular biological approaches to determine our strategy for the development of effective recombinant live vaccines to prevent M. pneumoniae and RSV infections by oral immunization. The success of our strategy may lead to the development of recombinant vaccines capable of protecting humans against other respiratory and/or gastro-intestinal tract pathogens.